The present invention relates to a gas turbine which includes a means to vary the gap between the stator and the rotor automatically in accordance with the temperature of the gas in the turbine. In a gas turbine, as in all other turbines and turbo-machines, it is desirable to maintain the play between the inner side of the stator housing and the top of the rotor blades as small as possible to obtain a blade system which is as tight as possible and therefore results in the smallest possible leakage of the active medium. In this connection, however, due regard must be paid to thermal changes in the system, which are great particularly in the case of gas turbines, and also to changes caused by rotational forces. The variation of the gap at the blade tip with time during a starting operation is normally such that the smallest gap occurs at a certain time, for example about 10 minutes, after a start, and then again increases because of different heating times for the stator and the rotor. To avoid seizure, the start gap must therefore be sufficiently large, which then results in the gap becoming undesirably large at the full load.